Electric control system for fuel oil burners



Dec; 15, 1931. L. L. SCOTT v 1,836,939

ELECTRIC CONTROL SYSTEM FOR FUEL OIL BURNERS Original Filed Nov. 20, 1922 F/e J ATTORN EY ing to the mumcral FOCHIIQCi to the rocker 4c.

Patented Dec.. 15, 1931 UNITED STATES PATENT OFFICE LEWIS L. SCOTT, OF ST. LOUIS,

MISSOURI, ASSIGNOR TO ELEOTROL, INC. OF MISSOURI,

ELECTRIC CONTROL SYSTEM FOR FUEL OIL BURNERS Continuation of application Serial No. 602,291, filed November 20, 1922. This application filed February 27, 1928. Serial No. 257,530.

This invention relates to novel automatic control apparatus particularly suited for use with domestic oil burners such as I show in my application No. 538,559, filed February 23, 1922, now Patent 1,644,496, granted October 4, 1927, and in my application No. 578,- 709, filed July 31; 1922. This application is a continuation of my' pending application, Serial No. 602,291, filed November 20, 1922.

One of the objects of my invention is to provide a means for controlling the ignition device for the fuel, whereby said fuel Wil not flow to the burner until theecontrol for the ignition device is in proper operating condition.

Further objects of my invention relate to certain novel details of construction and to combinations and operations of parts, all of which will more clearly appear from the detailed description to follow.

The invention is illustrated in the accompanying drawings in which; 7

Figure 1 is a front View of my electric control device showing a diagram of the wiring and different parts of the system.

Figure 2 is a top View of the contacts shown directly below line 11 of Figure 1.

Referring now to the drawings, the numeral 1 indicates a. board of insulating material on which the control switches are mounted. 2 indicates a glass tube which is partly filled with mercury and which has a pair of electric contacts at one end, which contacts are adapted to be closed or opened by the mercury accordangle at which said glass tube rests. A clip carries the tube 2 and is mounted on the rocker 4i, which rocker 4 pivoted at 5. rod 6 is attached. to rocker 4, and carries the adjustable weight 7, the purpose of which will he described later. 8 is a stop screw for limiting the throw of rocker 4. to the left. 9 is a lnracket for carrying the screw 8. The 11') indicates an armature which is The armature 10 is adapted to he acted on by the magnet 1.1 and when such action takes place, the tube 2 will tilt to the right and cause the mercury in said tube 2 to flow to ii" i right and, close fhc electric contacts at ilnli hand end of tube 2.

12 indicates the main h. 1 electric wi res which i plug 18. The wire yielding contact with core run to the transformer 13, and also to the motor 14: and transformer 15 through the contacts in mercury tube 2. 16 indicates a room thermostat which controls the current to the magnet 11 according to the temperature of the room in which said thermostat is located. Current for the room thermostat circuit is supplied by-the low voltage side of transformer 13. The low voltage side of transformer 15 supplies current to the spark coil 17 which spark coil 17 is connected to spark 19 of transformer 15 runs to yielding contact 20 and when contact 20 is touching contact 21 the current to the spark coil 17 is completed through the strip of thermostatic metal 22 which strip 22 is grounded as is one side of spark coil 17. It is necessary that the mercury tube 2 be tilted to the right before current will flow to motor 14 and transformer 15. The coil 23 is wound around the thermostatic metal 22 for the purpose of heating said metal 22 and causing same to move to the right and to open certain circuits which will be described in detail later. The coil 23 is connected in series with the coil 2st of the magnet 11. The wire25 of transformer 13 runs to coil 23 and wire 26 runs through room thermostat 16 to one end of coil 21 on magnet 11; the other end of the magnet coil 24 is connected to the core 27 of the magnet 11 and from core 27 runs to the contact post 28 which contact post 28 carries the contact screw 29. A flat spring 30 is secured under armature 10 so as to make a when current is going through magnet 11. The wire 31 is connected to contact spring 30 through rocker 4:; said wire 31 runs to the grounded contact post 32. The electric mo tor 14 operates the air blower wheel 33 and the fuel pump 34; the suction pipe 35 runs to a fuel tank (not shown) and the discharge ipe 36 runs to the fuel spray nozzle 37. Vhen the motor 1% starts fuel is pumped to spray nonzle 37 and air is furnished to the fuel spray by blower wheel and said fuel is ignited by the spark plug 18.

1 will now describe the action of my control stem.

Assuming that the mercury tube 2 is in 27 of magnet 11 the position shown in Figure 1 and that the contacts 20, 21 and 29 are all in proper contact with each other, upon closing of the thermostatic switch 16, current will flow from transformer 13 through the magnet coil 24, through contacts 29, 21 and 20 and through the coil 23 and back to the transformer 13. The instant'that current flows through magnet coil 24, the armature 10 will be attracted by the magnet 11 and the tube 2 will tilt t0 the right causing the mercury in said tube to flow to the right and close the circuit to motor 14 and transformer 15. The transformer 15 will furnish current to spark coil 17 asbefore described. The instant that the armature 10 is attracted by magnet 11, the spring will contact with core 27 of said magnet and a parallel electric circuit from coil 24 to coil 23 will be established through wire 31 as before described. As soon as the thermostatic strip 22 has been heated by coil 23 to the proper temperature, said strip 22 will move to the right and open the contacts 20, 21 and 29 as shown in Figures 1 and 2. Contact 20 is mounted on the yielding flat spring 20A so that when the thermostatic strip 22 moves to the right, contact 20 will move to the right a small amount so as to be out of engagement with screw 29. The opening of these contacts 20 and 29 breaks the circuit to one of the parallel circuits to magnet coil 24 and coil 23. The opening of contacts 21 and 20 breaks the circuit to the spark coil 17. It must be kept in mind, however, that current continues to flow through coils 23 and 24 because of the contact spring 30 on magnet core 27 as before described.

If the circuit to the room thermostat is broken or if the main line current is shut off, no current will flowthrough magnet coil 24 or coil 23 and the mercury tube 2 will instantly tilt to the left because of weight 7 and the circuit to motor'l4 and transformer 15 will be instantly broken. The immediate closing of room thermostat circuit or the main line circuit will not'start the motor until the thermostatic strip 22 has been cooled down so that it will'move to the left and first make the contact at 20 and 21, and then make the contact at 20 and 29. With this arrange- "ment it is impossible to, at any time, turn on the motor 14 until the circuit to spark coil 17 has been closed by contacts 20 and 21. I usually set the thermostatic strip 22 so that it will close contacts 20, 21 and 29 infrom one to two minutes after current is shut off;

from coil 23.

magnet.

situation as .above described, it might lead to undesirable results.

I claim:

1. In an oil burner control apparatus, electrically operated means for supplying fuel to the burner, means for igniting said uel, automatic means for controlling the ignition means, an electric switch operating in a high voltage circuit for controlling the electrica y operated means which supplies fuel to the burner,an automatic control device operating in a low voltage circuit for operating said high voltage switch, means for instantly opening the high voltage electric switch in the event that either the high or low voltage circuit is broken and means for preventing the closing of said high voltage switch until the automatic means for controlling the ignition device is in proper position to function. f

2. In an oil burner control apparatus, electrically operated means for supplying fuel to the burner, means for igniting said fuel, an

automatic device for controlling the operaan electric switch tion of the ignition means, for controlling the operation of the'electrically operated means for supplying fuel .to the burner, an automatic electric magnet for controlling said switch, said automatic magnet being so arranged in an electric circuit, that current for initially operating same is sent through a switch, for a short period of time, which is controlled by the automatic device which controls the ignition means, and a second switch in parallel with the last named switch, which is closed by action of theautomatic magnet when current is on same and which is open when current is not on same. i

' 3. In acontrol apparatus, amain automatic control switch, an electro-ma at for actuat mg .thesame, an electric circuit adapted to be closed through said magnet by closing said switch, a second automatic control switch controlling a parallel circuit through said magnet, means for preventing the operation of the main automatic control switch until the second control switch is in'position to properly function, a burner electrically operated means for supplying fuel to said burn er, an electrical device for igniting said fuel, a circuit controlledby said main operating switch for supplying current to said electrically operated means and said igniting device, and a second circuit governing the action of said igniting device and controlled by said second automatic control switch.

pair of worklng circuits,

electrically-operated means for supplying fuel to the burner and for igniting the fuel to be actuated thereby, respectively, a main automatic control switch for thecircuit of said fuel supply means, an electro-magnet for actuating the same, an

electric circuit adapted to be closed through said magnet by closing said switch, a second automatic control switch controlling a parallel circuit through said magnet and the circuit of said ignition device, and means for 5 preventing the operation of the main automatic control switch until the second control switch is in position to properly function.

5. In an oil burner control apparatus, in combination with two co-operating elec- 10 trically-operated devices, one of which is adapted to supply fuel to the burner and to operate in continuous fashion, and the other to ignite said fuel and to operate intermittently, working electrical circuits for said devices, a main automatic control switch controlling both of said circuits, a second automatic controlswitch governing the action of said main automatic control switch and controlling the circuit of said intermittently acting device, and means for preventing the operation of the main automatic control switch until the second control switch is in position to properl function.

6. In oi burner electrically-controlled apparatus, a pair of working electrical circuits, one. a high voltage circuit, and the other, a low voltage transformer circuit, electricallyoperated apparatus for supplying fuel to the burner in said high voltage circuit, an ignition device in the other circuit, a main automatic control switch controlling both of said circuits, a second automatic control switch located in said low voltage circuit and governing the action of said main automatic control switch and controlling the circuit of said ignition device, and means for preventing the operation of the main automatic control switch until the second control switch is in position to properly function.

7. In an oil burner control apparatus, electrically operated means for supplying fuel to the burner, means for igniting said fuel, an electric switch for controlling the o eration of the electrically operated means or supplying fuel to the burner, an automatic electric magnet for controlling said switch, a room thermostat for controlling the current to the automatic electric magnet and connected in series with said magnet, a thermostatically operated switch which controls the current flow, for a short period of time, for initially operating said automatic electric magnet, a secondswit-ch in parallel with said thermostatically operated switch, which is closed by action of the automatic electric magnet when current is on same, and which is open when current is not on same.

8. In an oil burner control apparatus, electrically operated means for supplying fuel to the burner, means for igniting said fuel, automatic means for controlling the ignition means, an electric switch for controlling the operation of the electrically operated means for supplying fuel to the burner, an automatic electric magnet for controlling said switch, a room thermostat for controlling the current to the automatic electric magnet and connected in series with said ma et, a thermostatically o erated switch whic con trols the current ow, for a short period of time, for initially operating said automatic electric magnet, a fixed contact cooperating with said thermostatically operated switch, a yielding contact interposed between said fixed contact and said thermostatically operated switch, which yielding contact controls the time of operation of the ignition means, a second switch in parallel with said thermostatically operated switch, which is closed by action of the automatic electric magnet when current is on same, and which is open when current is not on same.

In testimony whereof, I have hereunto set my hand, this 17th da of February, 1928.

IYEWIS L. SCOTT. 

